Storyteller has a change of heart in the den (4)
I believe the answer is:
lair
'den' is the definition.
(I know that den can be written as lair)
'storyteller has a change of heart in' is the wordplay.
'storyteller has' becomes 'lr' (I can't explain this - if you can you should give a lot more credence to this answer).
'a change' becomes 'gait' (gait is a kind of change).
'of heart' indicates the central letters (I've seen 'heart of' mean this).
'in' indicates putting letters inside.
The middle letters of 'gait' are 'ai'.
'lr' placed around 'ai' is 'LAIR'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for lair that I've seen before include "Wild animal's place of refuge" , "Habitation of a wild animal" , "Habitat of a wild animal" , "Rail about wild animal's home" , "office?" .)